Mercury switch



Au 25, 1931. a P, K; AMBLET 1,820,300

mmcuay SWITCH Filed Feb. 23, 1926 INVENTOR. PAUL ff CPA/1451 57? raeaea Aug. 25; ieai UNITED STATES PATENT OFFICE PAUL K. CRAMBLET', or MILWAUKEE, wiso'oNsIN', ASSIGNOR, BY MESNE ASSIGNMENTS, T MINNEAPOLIS-HONEYWELL REGULATOR COMPANY, OF MINNEAPOLIS, MIN- NESOTA, A CORPORATION OF'DELAWARE- g 'MER-cuRY swrcrorr Application filed February 23, 1926. Serial No. 89,838.

This invention relates to improvements in switches of the'mercury contactor type, and

has been-designed more particularly as an improvement upon and further development of my invention as disclosed in my copending application for mercury switches filed September 23, 1926, Serial 'No. 89,387.

In the copending application referred to, the chief object in view was to provide an improved .switch of the type mentioned wherein a mercury to mercury make and break could be obtained in an envelope of any of the ordinary soft glass types by con fining it to a point removedfrom the walls of the envelope, thus realizing the many advantages of the mercury .to mercury operation, while avoiding the various disadvantages heretofore encountered.

The present invention has this same object in view, but attacks'the subject along lines not specifically disclosed in the application referred'to, although broadly contemplated thereby. Thus, the present invention contemplates and has for one of its objectives the provision of improved means in the way of construction and arrangement of the parts all tending towards what is believed to be a more practical and commercial development and a more satisfactory solution of the various problems encountered.

Other objects will appear from the following specification .taken in connection with the accompanying drawings wherein several forms of the invention are illustrated.-

, In the drawings:

Figure 1 is a longitudinal sectional view of a mercury switch constructed in accordancewith the-present'invention;

Fig. 2 is a sectional v1ew takenon the line 22 of Fig.1; i

Fig. 3 is a longitudinal sectional view taken through a switch similar to that shown in. Fig.' 1, butmodified to provide for the simultaneous making of one circuit upon the breaking of another. a

Fig. 4 is a longitudinal'sectional viewof a mercury switch showing the inner tube and outer envelope welded or otherwise integrally oinecl together;

Figs.- 5, 6, 7 and 8 are longitudinal secreferred to, my aim in the development of j the switches shown in the drawings and hereinafter described in detail, has been to realize a' mercury to, mercury make and break in a switch employing a soft glass envelope or container. As is well known, no envelope of such construction will stand such operation where the make and break occurs on the wall of the envelope. Such operation is feasible in switches employing envelopes of quartz or hard glass such as Pyrex and the like, but in the manufacture of such switches many drawbacks and obstacles are encountered which render the switches difficult of production and consequently more costly than those of the soft glass envelope type. In arriving at a realization of my objective, I have constantlyhad in mind the idea or thought of confining the, point or zone of make and break to a location removed from the walls of the envelope so as to effectively provide against injury to the latter. The present invention contemplates improved means of a practical and commercial nature of controlling or confining the arcing zone to such point.

Referring more in detail to the drawings and first to Figure 1 thereof, the switch,

which is shown in circuit making position,

comprises the outer sealed envelope 10 which, as already stated, is preferably, for commercial and economical reasons, made of glass of'thesofter varieties. Mounted within the envelope 10 near one end thereof a ferrule lope, this tube projecting at its larger end into the opening in the ring and being cemented or otherwise secured therein substantially as shown. This tube 12 is open at both ends, its free or unsupported end, however, being preferably reduced as at 12 and flattened out-or elongated transversely of the longitudinal axis of the envelope substantially as shown in Fig. 2. I The electrodes are shown at 13 and 14, both being sealed in the walls of the envelope at opposite ends, the first extending into the inner tube 12 and lying along the lower wall thereof, terminating slightly short of the reduced snout or mouth at the free end of the tube. The other electrode 14 projects downwardly to a point near the lower wall of the envelope and between such wall and the tube 12. A body of mercury 15 is placed in the envelope sub stantially in the amount shown, this mercury being partly on one side of the fibrous ring or partition 11 and partly on the other side thereof, such parts being united into a single continuous body when the tube is tilted to circuit making position substantially as shown in Figure 1. As will be observed, the body of mercury after separation thereof into two portions, one on one'side and one on the other side'of partition 11, reunites in g a single body again upon tilting of the tube,

as shown, and "in thus reuniting, the portion to the right of partition 11 in Fig. 1 flows along the lower wall of the envelope and then upwardly over the end wall thereof meeting the otherportion of mercury which simultaneously flows through the tube 12 towards the restricted end thereof, the quantity ofv mercury and the general construction and arrangement of parts being such as to definitely bring about this making and breaking between these two portions of mercury within the restricted mouth or snout of the tube 12 substantially at the point Thus, any arcing which may occur at the make or the break occurs at thispoint which, as will be observed, is located substan-' tially at the longitudinal axis of the envelopeand at a substantial distance from both ends thereof. Thus, the envelopeis protected against all the deteriorating influences of the arcl' In order to provide against injury to the tube 12, due to the confining of the making and breaking point within the outer end thereof, said tube is preferably constructed of quartz or hard glass such as Pyrex and the like which, as is well known, are substantiallyunaffected by the sudden and high temperature changes such as are incident to the arcing.

.As-is well known, it is the common practice inthe-use of mercury switches to mount them so that they may be oscillated, first in one direction to make the circuit and then in the other direction to break it. The switch shown in Figure 1 has been designed for operation infthis manner and has proved, in actual tests,-to represent a substantial adactual operation and also in its ability to withstand hard usage and comparatively heavy currents.

The switch illustrated in Figure 3 of the drawings represents a modification of the one just described the modification involving an I arrangement whereby the switch maybe employed in the control of two circuits in such wise that one of said circuits is simultaneously made'with' the breaking of the other.

The outer sealed envelope in this figure bears reference character 16, the fibrous ring or partition 17 and the inner tube 18. In the form of the invention illustrated in this fig ure, the partition 17 is mounted within the envelope 16 substantially midway between the ends thereof, and the tube 18 is doubleended and mounted within the partition 17 midway of its ends so as to provide for the double action already referred to. The three electrodes bear reference characters 19, 20 and 21. The electrode 19, which is common to the two circuits to be controlled, projects through a small opening 22 in the tube 18 and thence downwardly and along the lower wall of said tube, while the electrodes 20 and 21 project through opposite ends of the envelope and then downwardly to a point near the lower wall thereof and between the latter and the tube. The body'of mercury 23 is in such quantity thatupon a given oscillation of the envelope, the circuit between electrodes 19 and 20 will be broken substantially at the point 24 in the snout or mouth at the lefthand end of the tube in Fig. 3, and simultaneous with such breaking at the point 24 the two bodies of mercury will flow together at the point 25 in the mouth at the opposite of such make and break at each end ofthe switch is definitely confined to the mouth of the inner tube and at points substantially removed from the walls of the envelope. In this modification, as in the form shown in Fig. ,1, the 'outer envelope-,may preferably be of soft glass, while the tube 1 8 may be of quartz or of some suitable hard glass construction.

In Figure 4 a further modification is illustrated, in which both theouter envelope and the inner tube are of quartz or hard glass construction'and welded or'otherwise integrally secured together as at 26. As is well known, it'is not possible to Weld or otherwise integrally unite a hard glass, for in stance, with a soft glass; in other words, glass welding is largely confined to the uniting of glass of the same or substantially the same 7 composition. In a construction such as shown in Fig. 4, therefore, in which the inner tube the tube and envelope must, of necessity, be

glass, quartz'or the like in the formation of the inner tube, due to the location of the arcing zone within the outer end thereof, an-

outer envelope of hard glass is necessitated in order that the welding maybe properly performedfiThe arrangement of the inner tube and the outer envelope/in this modification, as well as the-arrangement of electrodes and the location of the arcing zone, etc., are

i substantially the same as in the form of the inventi en first described, and need not, therefore, be described in detail.

In the form of the invention shownin Figure 5 of the drawings, a substantially shorter tube 27 is employed, this tube, however, being provided with-a mouth or snout 28 of substantially the same foi mation as in Figure 1 and being secured at its other end in the opening of the ring 29 and supported by thejlatter in the same way as previously described. The ring 29 is also preferably of fibrous material and cemented to the walls of the envelope, but in View of the shbrtness of the tube 27, it has been found advantageous to position the ring substantially as shown, or in other words, so that the mouth'28 of the tube will lie substantially in the same position with respect to the adjaecntend of the envelope as. in the form shown in Figure 1. This provides a much bigger chan'iber to the left of thepartition and a smaller chamber'to the right thereof than in the forms p-r viously described. Accordingly, a much s aller quantity of mercury may be used, while at the same time, with the proper control of oscillation and gauging of distances and the quantity of mercury, themake and break between the two bodies of mercurymay be effected within the mouth or neck 28 of the tube substantially the same as previously described in connection with Figure -1. c

InFigure G of the drawings, the tube30 takes the form of a more ferrule orv straight cylindrical ring concentrically" arranged within the fibrous ring or partition 31 and flush at its endswith the ends of the latter. The electrodes 32 and 33"project through opposite ends of, the envelope 34 and then extend downwardly to points near the lower wall of the envelope and-1n quite close proximity to the partition. Only a small quantity of mercury is necessary in a switchconstructs 7 ed in this manner, the parts being so arranged that the make and break between the .two

bodies of mercury occurs immediately with in the tube 30, preferably substantially centrally between the opposite ends thereof. Thus. the same thought, namely, the contining of the arcing zone to a point removed from, the walls of theenvelope. is preservml in this switch. the same as in those previously described. The tube 30, as in the other forms of the invention,- is preferably formed of quartz or Pyrex so as to be unaffected by the deteriorating influences of the are.

In Figure 7 a further modification of the invention is illustrated. This switch is designed for special service and is operated shuttle fashion, or in other words, makes and breaks the circuit upon a rapid reciprocation back and forth parallel to its longitudinal axis. The partition 35 is mounted in the envelope 36 in rather close proximity to one end of the latter, and a quartz or hard glass tube 37 is carried by thepartition in the same manner as described in the previous embodiments, this tube, however, differing in construction and arrangement from those previously described in that it is bent downwardly just in advance of the partition 35 and then outwardly or forwardly just about the lower wall of the envelope, terminating at a point near the other end of-the latter. A small opening 38 is provided'in the upper wall of the tube 37 near the outer end thereof and mercury 39 substantially in the amount shown isplaced in the envelope 7 and, of course, a portion thereof flows through the opening 38 in the tube 37. It Will be observed thatupon operation ofthe switch in the manner just described, the mercury in the envelope outside the tube 37 will, as the switch isv thrust forwardly, be jarred or displaced rearwardly within the envelope out of contact with the mercury in the tube 37 ,thus breaking the circuit. Then, upon reverse novementof the switch, the body of mercury thus displaced will be moved in the other direction and make contact with that-in the tube. The electrodes are shown at 40 and 41, the former extending into the envelope along'the'lower wall thereof intermediate the tube and said Wall, .while the electrode 41 extends through the opposite end of the envelope and down into the tube 37 to a point where cont'nuous .contact with the mercury in said tube is as- "sured. In this modification the tube 37is also preferably of quartz or'hard glass, while the opening 38 in the tube 37 and, as will be observed, completely removed fromthe walls of the envelope,-thus avoiding, all danger of the arcing damaging or injuring the en'- Velope.

In-Figure 8, a special electrode formation is illustrated as applied to the form of the invention first described, enabling the switch,

after-it has been operated for a long period of time in. one position, to be inverted or turned around through 180 degrees and theoperation continued. It has beenfound in actual practice that the constantarching in the mouth or snout of the inner tube is conof quartz or hard glass, causes or produces certain minute disintegration and the grad ual eating away of the lip. In the switch shown in Fig. 8, a mere half rotation of the envelope will move the disintegrated lip up. over the sparking zone and present a fresh surface over which the make and break may occurto thus materially enhance the life of the switch. In this figure, the outer envelope bears referencecharacter 42, the fibrous partition 43, the inner tube 44 and the electrodes 45 and 46, respectively. The inner end of the.

electrode 45, in order to permit of the operation above described, may be curved in half-circle fashion, for instance, as shown at 47', while the end of the electrode 46 within the envelope may be similarly curved or bent so that these ends will provide contact with the body of mercury 48 in either position of the switch. a K i In Figures 9 and 10, cross-sectional views taken through switches of substantially the same"construction illustrated in Figure 1,

are shown, these figures, however, showing modifications of the mouth or restricted end of. the inner tube. These modifications have been designed with the same thought in "mind as outlined above in connection with Figure 8 in order to enhance the life of the switch by shifting it on its longitudinal axis in order to shift the point of arc concentration on the lip of thc'tube- In Figure 9, the mouth of the tube is shown restricted as at 49 but terminating in a circular opening, rather than the flattened out (ii-elongated. slotlike opening shown in Fig. 2, for instance. By forming the end of the tube in this fashion,

the switch can be gradually rotated from time to time through a complete 360 degrees,

thus shifting the point of are concentration completely around the opening thereby greatly retarding the disintegrating effects of the are. In Figure 10 the inner tube is shown "'"as provided with the transversely. elongated lower lip 50 and a substantially round or semi-cylindrical upper lip 51.. In a switch employing a neck shaped in this fashion the lower lip, upon disintegration to any appreciable extent, could be shifted upwardly over the arcing zone, thus presenting the semi-cylindrical lip to. the make and break action, and in View of the curvature of said lip, "gradual rotation of the switch on its longitudinal axis in either direction could be employed in materially retarding the dis-' integrating action. As shown. the elcctrcdes in switches such as shown in Figures 9 and 10, would be shaped similarly to those shown in Figure 8, for instance, so that the same would at all times make contact with the body of mercury regardless of the angular adjustment of the switch.

Another feature of .the present invention contemplates an improved method of construction. The supporting of the inner tube within the outer sealed envelope by means of the interposed ring or ferrule of fibrous material has already been referred to, but as this feature forms an important part of these switches bothfrom the standpoints of manufacture and operation, it is desired to further amplify the same. The method of,

manufacture of these switches, aside of course from the ones shown in Figure 4 whichis a glass welding job, first involves the formation of the inner tube. Asbestos paper tape is then Wound tightly upon the large or ,supported end of the tube 12 until of substantially the same diameter as the inner diameter of the envelope. Before sealing the envelope, the tube 12, is inserted in position therein with the ring of asbestos tape firmly engaging the walls thereof. A suitable cement is then applied to the ring oftape especially where it contacts with the Walls of the envelope and wall of the tube. This method has proved Very satisfactory in prac: tice and has proved to result in mercurytight jointsbetween the tube and fibrous ring and the envelopeand said ring, andto provide a very substantial connection and support for the inner tube. The electrodes are then sealed through the walls of the envelope and the air exhausted and the usual inert gas such as hydrogen substituted, and the envelope then sealed off as indicated throughout the figures by the reference character 60. \Voven asbestos tape has also been used with good results in the formation of the supportlng ring for the inner tube, and a ring of this kind may be sealed or cemented in position in the same manner as just described in connec- V tion with the use of asbestos paper tape.

It will be observed that in constructingthe switch in the manner just previously described, the inner tube is supported within and out of contact withthe outer sealed en; velope by means of What may be termed a cushi0n, or in other words, a substance ca pable of yielding to compensate for any relative movement between the inner and outer glass members without danger of disturbing or breaking the mercury seal and without danger of injury of any kind to the glass members themselves. This is an important feature, as it provides aswitch capable of in this, likewise, it is desired that the append- 2 ed claims be interpreted broadly and of a scope commensurate with the spirit of the invention,- and not limited or restricted in any manner to the particular embodiments of the invention shown.

The invention claimed is:

p1. A mercury switch of the character described comprising an outer envelope, a protective sleeve of are resistant material disposed in said envelope out of contact with the walls thereof, said sleeve being open at both ends and providing. a passageway between one end of said envelope and the other end thereof, a ring-like supporting member and pariition interposed between the sleeve and the outer envelope, layers of cement uniting I thesupporting member to the sleeve and to lfv supported therein out of contact therewith,

a body of mercury in said envelope and electrodes making contact with said mercury, the support for said tube being of fibrous material cemented to the latter and to the walls of said envelope and providing a ringlike mercury-tight obstruction in the space between the walls of the tube and envelope, thus confining the flow of mercury from one end of the envelopeto the other tosaid tube.

. A mercury switch of the character described comprising a hermetically sealed outer envelope, a protective sleeve of are resisting mater al disposed in the outer en velope and out of contact wlth the walls "thereof, a cement impregnated supporting member interposed between the outer en-- velope and the protective sleeve and a body of mercury in the outer envelope adapted to unite and divide within the sleeve.

4. A mercury switch comprising a hermeticallyi sealed envelope, an open-ended tube supported therein out of contact and out of direct connection with the Walls of said envelope and providing the only passage between opposite ends of said envelope, two bodies of mercury in said envelope, one. at each .end thereof, and adapted to flow together atone end of said tube upon tilting of said envelope in one direction and to separate at said end upon reverse tilting of the-envelope, and electrodes'in constant contact with said bodies of mercury, respectively, the end of said tube at which the make and break occur being reduced in size and elongated in cross section.

5. In a mercury switch, an envelope, an open-ended tube therein, cushioning mercury tight supporting means interposed between said envelope and tube, an electrode in said tube, a second electrode in said envelope outside said tube, and mercury in said envelope in such quantity as to ensure a mercury to mercury make and break within said tube upon oscillation of the switch.

6. In a mercury switch, an envelope, an open-ended tube therein, cushioning mercury tight supporting means interposed between said envelope and tube, an electrode in said tube, a second electrode in said envelope outside said tube, and mercury in said envelope in such quantity as to ensure a mercury to mercury make and break within said tube upon oscillation of the switch, the make and break occurring at substantially a fixed point within said tube.

7. In a mercury switch, an envelope, an

open-ended tube therein, cushioning mercury tight supporting means interposed between sald envelope and tube, an electrode in said tube, a second electrode in said envelope outside said tube, and mercury in said envelope in such quantity as to ensure a mercury to mercury make and break within said tube upon oscillation of the switch, the make and break occurring at substantially a fixed point within said tube, such point being confined within one end of said tube.

. 8. In a mercury switch, an envelope, an open-ended tube therein, cushioning mercury tight supporting means: interposed between said envelope and tube, an electrode in said tube, a second electrode in said envelope outside said tube, and mercury in sald envelope --in such quantity as to ensure a mercury to mercury makeand. break within said tube upon oscillation of the switch, the make and break occurring at substantially a fixed point within said tube, such point being confined within one end of said tube and said tube being formed of a substance capable of with-' 1;,

standing high temperatures and rapid temperature fluctuations.-

' v9. In amercury switch, an envelope, an open-ended tube therein, cushioning mercury tight supporting means interposed between 3 said envelope and tube, an electrode 111 said tube, a second electrode in said envelope outside said tube, and mercury in said envelope 1n such quantlty as to ensure a mercury to mercury make and break within said tube upon oscillation of the switch, the make and break occurrin at substantially a fixed point within said tube, such point being confined within one end of said tube, said tube being formed of a substance capable of withstanding high temperatures and rapid temperature fluctuations, and said envelope being of soft glass-composition.

10. In a mercuryswitch, an envelope, an open-ended tube therein, a ring of cement roe impregnated asbestos interposed between thewalls of said tube and envelope for supporting the former and providing a seal for the space between said tube and envelope, and mercury in said envelope separating at a pointwithin said tube into two bodies upon oscillation of said switch in one direction, said two bodies flowing towards each other upon oscillation in the other direction and meeting within .said tube, and electrodes sealed.- in said envelope and making contact with said bodies of mercury, respectively.

11. In a mercury switch, an envelope, an

open-ended tube therein, a. ring of cement impregnated asbestos interposed between the walls of said tube and envelope for supporting the former and providing a. seal for the space between said tube and envelope, and mercury in sald envelope separating at a point within said tube into two bodies upon oscillation of said switch in one direction, said two bodies flowing towards each other upon oscillation in the other direction and meeting at one end of said tube, and electrodes sealed in said envelope andcontacting' with said-bodies ofmercury, respectively. O

12. A mercury switch comprising a her metically sealed envelope, an open-ended tube supported therein out of contact with the walls of said envelope and providing the only passage between opposite ends of said envelope, two bodies of mercury'in said envelope, one at each end thereof, and adapted to flow together at one endof said tube upon tilting of said envelope in one direction and to separate at .said end upon reverse tilting of the envelope, and electrodes in constant contact with said bodies of mercury, respectively, the end of said tube at which the make and break occur being reduced in size" and elongated in cross section, said electrodes being so shaped at their ends as to makecontact with said mercury regardless of the angular adjustment of said envelope on its longitudinal axis.

13.-A mercury switch comprising a hermetically sealed envelope, an open-ended tube supported therein out of contact and out of direct connection with the walls of said envelope and providing the only passage between opposite ends of said envelope, two bodies of mercury in said envelope, one at each end thereof, and adapted to flow to gether at one end of said tube upon tilting of said envelope in one direction and to separate at said end upon reverse tilting of the envelope, and electrodes in constant contact with said bodies of mercury, respectively, the end of said tube at which the make and break occur being reduced in sizeto tend to cause the mercury to mercury make and break within theconfines of said reduced end and to minimize arcing.

14. A mercury swltchcomprismg a hermetically sealed envelope, an open-ended tube supported therein out of contact with the walls of said envelope and providing the only passage between opposite ends of said envelope, two bodies of mercury in said envelope, one at each end thereof, and adapted to flow together at one end of said tube upon tilting of said envelope'in one direction and to separate at said end upon reverse tilting of the envelope, and electrodes in constant contact with said bodies of mercury, respectively, the end of said tube at which the of shocks, strains and stresses between the tubeand the envelope, and a body of mercury having a portion in the tube and a portion in the envelope and Without the tube in the open position of the switch, said portions pf the mercury making and breaking contact witheach other on a surface of and within .the tube.

16. A mercury switch comprising an outer envelope, an elongated tube constituted of a substance capable of withstanding high temperatures and rapid temperature fluctuations and disposed in said envelope with its interior communicating with the interior of the envelope, a combined partition and supporting member fixedly supporting said tube in the envelope out of contact therewlth and in such manner as to minimize trans- I ngissions of shocks, strains and stresses tween the tube and the envelope, said tr "e projecting longitudinally of the envelope,

and beyond its combined partition and sup porting member and coacting therewith and with the envelope to provide a confined space outside of the tube but within the outer envelopeQand a body of mercury having a portion in the tube and a portion in said confined space in the open position of the switch, said portions of the mercury upon tilting of the switch about an axis extending transwersely thereof rolling within the tube and withinthe confined space outside of the tube during the making and breaking operations and uniting and: dividing Within the tube 1 and on the surface thereof.

In witness whereof I hereto aflix my signature.

PAUL K. CRAMB'LET. 

